Ambient temps work well for hatchlings - subadults, when maintained at 80-82 degrees (F). We maintain our adults at these temperatures as well, but also provide a warmer spot in the enclosure of 86-87 degrees (F).
48" x 24" x 15" is a good cage size (i.e. Animal Plastics T-10 enclosure):
Here's some additional care info you may find helpful:
http://bloodpythons.com/index.php/bl...ve-environment